Line break control

ABSTRACT

This invention is directed to a system for detecting pressure drops in a flow line, the same being indicative of a line break. Reduced pressure is communicated to one side of a diaphragm. A similar reduction is communicated much more slowly to the other side by virtue of series connected oil reservoirs having an orifice therebetween. The pressure differential on opposite diaphragm sides causes valve closure.

Gulick Feb. 26, 1974 [54] LINE BREAK CONTROL 2,589,373 3/1952 Hammock137/599 [75] Inventor: Ronald A. Gulick, Houston, Tex. n 73] Assignee;Research Engineering Company, 2,072,314 3/1937 Rhodes 137/460 Houston,Tex. Filed Nov 20 1972 Primary Examiner-Harold W. Weakley [21] Appl. No:308,026 [57] ABSTRACT [52] U S Cu 137/486 137/599 This invention isdirected to a system for detecting [51] Fl6k 17/20 pressure drops in aflow line, the same being indicative [58] Fie'ld 6 494 460 of a linebreak. Reduced pressure is communicated to one side of a diaphragm. Asimilar reduction is com- [56] References Cited municated much moreslowly to the other side by virtue of series connected oil reservoirshaving an orifice UNITED STATES PATENTS therebetween. The pressuredifferential on opposite fihafer 137/460 X diaphragm sides causes valveclosure. ulien 3,612,081 10/1971 Williams 137/460 X 5 Claims, 2 DrawingFigures LINE BREAK coNTnoL BACKGROUND OF THE INVENTION Whenever materialis caused to flow through a pipe line, there is concern with linebreakage,-which disrupts service and loses material. Prior systems havepositioned spaced valves throughout the line for effecting materialcutoff, in the event of a break. Valve control has been manually, aswell as automatically actuatable by pneumatic or hydraulic means. Someprior systems have utilized pressure difierentials, transmitted toopposite sides of a diaphragm, to cause valve actuation, therebyshutting down the line. One of the means heretofore suggested as a meansfor causing such pressure differential has been the positioning of anorifice in a gas or other fluid passing system. Gas would enter onediaphragm chamber without passing through the orifice, and the otheronly after passing through the orifice. Naturally, if the gas is linegas or line gas controlled, then when a break occurs, the line pressurewould drop. This was almost immediately communicated to one diaphragmchamber. However because of the orifice limitation, the drop would becommunicated such more slowly to the other side, resulting in a pressuredifferential. While this system was effective when operative, limitationbecame apparent. Such gas controlled systems contained contaminants. Aprime difficulty encountered was the build-up of such contaminantsaround and in the orifice. This has made regulation difficult, andresulted in periodic shutdowns for maintenance or parts replacement.This is the problem area to which this invention is directed.

SUMMARY OF THE INVENTION A diaphragm permits an actuator to open orclose a valve, which valve is positioned in a line. The downstream linepressure is communicated directly to one side of the diaphragm. Thus, ona break occurring a pressure drop will be so communicated. This samedownstream line pressure is communicated to one of a pair of oilreservoirs, they being series connected by virtue of an orificecontaining conduit. On a pressure drop occurring, the tendency of theconnected reservoirs to equalize pressure will cause oil flow throughthe connecting conduit. The orifice will, however, restrict movement,and therefore slow down the pressure change. Since one side of areservoir is in pressure communication with the opposite diaphragm sidefrom that initially described, it is seen that a pressure imbalance willbe created, causing the actuator to close the valve.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of thesystem comprising this invention, and

FIG. 1A is a detail of the orifice shown within the phantom lines ofFIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT The drawings indicate a conduit,representing a pipeline, at It). The passage or flow of fluids ormaterial through this line, in the direction of the arrow, is regulatedby valve llll, which may be one of a number of valve types. The openingor closing of valve 11 would be controlled by a valve actuator,generally illustrated at 20. Such actuators, being common in the art,need not be described fully herein, one type being illustrated in US.Pat. No. 3,640,140.

The downstream end 12 of line 10 is pressure connected to the valveactuator by the structure described hereinbelow.

End 12 is linked to one side of diaphragm chamber 30, the diaphragmbeing illustrated at 31. The same end I2 is also connected to the upperportion 41 of pressure vessel 40. This vessel comprises part of thesignificant improvement of this invention. Such improvement is generallyenclosed Within the dashed line area. The lower end of vessel 40communicates with the lower end of a similar vessel 50, by virtue of aconduit 45, said conduit containing an orifice device d6, whichrestricts passage of fluid through such conduit. The upper end 51 ofvessel 50 is connected by a conduit to diaphragm chamber 30, oppositethe juncture of the conduit leading from portions 41 of vessel 40. Oil,or similar viscous and relatively inert fluid fills approximately thelower one-half of each vessels $050, to the dashed level indicated. Linegas would fill the top portion of vessel 40. Some other available gas,such as N2 may be used within the system comprising the upper portion ofvessel 50, the lower portion of the diaphragm chamber,

and the conduit connection therebetween. Upward movement of thediaphragm would have to overcome the biasing means depicted byspring-block 70. In the event of such upward movement, a snap actioncontrol system would become activated. This control system, whilevariable, might comprise an activator lug 71 movable with the diaphragm,and spring-biased lever arm 72, which on being displaced beyond anapproximate mid position would quickly move or pivot to a furtherposition. On such pivoting occurring,the valve system schematicallyillustrated at which connects an outside source of power (not shown)such as air under pressure, to actuator 20, would connect such source soas to cause the actuator to close the valve. The valve system may becontrolled by a solenoid which in I turn would be under the control of aball check valve system such as indicated at 100. It may be repeatedthat for purposes of this invention, the system for translatingdiaphragm movement into actuatorcontrol of valve 1 1, may be varied.

The operation would be as follows. Normally, valve 11 would be open,material would be flowing through line 12, and the pressure would beevenly balanced within diaphragm chamber 30 on opposite sides of thediaphragm. If a break occurs downstream of valve 11, the pressure wouldautomatically drop. This drop would almost immediately be communicatedto the chamber 30 above the diaphragm, as well as to pressure vessel 40,above the oil level. Since orifice 46 acts to restrict the flow ofmaterial from one vessel to the other, the pressure within vessel 50remains high, until the fluid gradually bleeds through the orifice.Thus, during this initial period, due to the conduit joining vessel 50and the underside of chamber 30, such underside is under a higherpressure than above. This would cause upward diaphragm movement,alongwith attached lug 711, and thereby cause lever 72 to pivot upwardly.Such pivoting would open the ball of check valve 100, so as to actuatesolenoid 90, and thereby so connect the outside power source to actuator20 as to cause valve 11 to close. It may be noted that the drawingillustrates a connection between the downstream side E2 of line 10 andball valve 100. On a break occurring, downward pressure on the ball ofvalve 100 would be reduced,

thereby easing the force that would otherwise resist the snap action oflever 72.

The detail of FIG. 1A, illustrates the adjustability of the orificefeature. A disc, roll or similar structural member may include a numberof passage orifices, so that on movement, much like a valve element,orifices of different sizes may be chosen and positioned on line. Anumber of such orifices 46 are indicated in FIG. 1A. A furtheradjustable feature would include the provision of a conduit 200, havinga needle valve adjustment 201, therein, all being in parallel to conduit45. This would permit fluid moving from one of vessels 40 or 50, to theother, to at least partially bypass or shunt the orifice. Thus, at least2 of regulation are provided, which provide the sensitive controlsdesired.

While only limited embodiments have been described, certainmodifications might be made without departing from the spirit of theinvention, the scope of which is intended to be limited only by thefollowing appended claims.

I claim:

1. A system for controlling a line break in a product line, comprising:

A. diaphragm housing including chambers on opposite sides of adiaphragm;

B. first means for pressure communication between a product line and oneof said diaphragm chambers; and

C. means for causing a pressure imbalance between said chambers on abreak occurring in said line,

said imbalance causing means including:

1. time delay means for delaying pressure communication between saidproduct line and the other of said diaphragm chambers, said time delaymeans including:

a. a pair of spaced vessels intermediate said product line and saidother diaphragm chamber, b. said vessels being adapted to haverelatively inert liquid filling a substantial portion of said vessels,

0. first conduit means connecting the liquidcontaining portions of saidvessels, and

d. orifice means positioned in said first conduit means,

2. second conduit means communicating between said product line and thenon-liquid containing portion of one of said vessels, and

3. third conduit means communicating between said other of saiddiaphragm chambers and the non-liquid containing portion of the other ofsaid vessels.

2. The system of claim 1 wherein each of said vessels has a portionadapted to receive other fluid other than said relatively inert liquid,said other fluid being isolated from said orifice means.

3. The system of claim 1, wherein said orifice means includes means forselectively positioning, in said first conduit means, a plurality ofdifferently sized orifices.

4. The system of claim 1, wherein said first conduit means includes aline parallel to said orifice means, said parallel line having thereinmeans for adjustably controlling liquid flow through said parallel line.

5. The system of claim 1 wherein said first conduit means includes a)means for selectively positioning therein one of a plurality ofdifferently sized orifices, and b) a further liquid passing lineparallel to said orifice means, said parallel line having therein meansfor adjustably controlling liquid flow through said parallel line.

1. A system for controlling a line break in a product line, comprising:A. diaphragm housing including chambers on opposite sides of adiaphragm; B. first means for pressure communication between a productline and one of said diaphragm chambers; and C. means for causing apressure imbalance between said chambers on a break occurring in saidline, said imbalance causing means including:
 1. time delay means fordelaying pressure communication between said product line and the otherof said diaphragm chambers, said time delay means including: a. a pairof spaced vessels intermediate said product line and said otherdiaphragm chamber, b. said vessels being adapted to have relativelyinert liquid filling a substantial portion of said vessels, c. firstconduit means connecting the liquid-containing portions of said vessels,and d. orifice means positioned in said first conduit means,
 2. secondconduit means communicating between said product line and the non-liquidcontaining portion of one of said vessels, and
 3. third conduit meanscommunicating between said other of said diaphragm chambers and thenon-liquid containing portion of the other of said vessels.
 2. Thesystem of claim 1 wherein each of said vessels has a portion adapted toreceive other fluid other than said relatively inert liquid, said otherfluid being isolated from said orifice means.
 2. second conduit meanscommunicating between said product line and the non-liquid containingportion of one of said vessels, and
 3. third conduit means communicatingbetween said other of said diaphragm chambers and the non-liquidcontaining portion of the other of said vessels.
 3. The system of claim1, wherein said orifice means includes means for selectivelypositioning, in said first conduit means, a plurality of differentlysized orifices.
 4. The system of claim 1, wherein said first conduitmeans includes a line parallel to said orifice means, said parallel linehaving therein means for adjustably controlling liquid flow through saidparallel line.
 5. The system of claim 1 wherein said first conduit meansincludes a) means for selectively positioning therein one of a pluralityof differently sized orifices, and b) a further liquid passing lineparallel to said orifice means, said parallel line having therein meansfor adjustably controlling liquid flow through said parallel line.